Method of making balls



April 1, 1930.

J. R. GAMMETER METHOD OF MAKING BALLS Filed Nov. 2, 1927 JHL/E'HZ'UE v {JD/9Z7 .53 551 71 752 22 Patented Apr. 1, 1930" UNITED STATES PATENT OFFICE JOHN R. GAMME'IER, onAKnoN, onto, nssrenon To a. e. srannine nnn 1330s., A

' CORPORATION or NEW JERSEY METHOD or MAKING BALLS Application filed November 2, 1927. Serial No. 230,493.

This invention relates to balls having gasfilled centers, for. lightness or resilience or both, and to methods of making the same.

My chief objects are to provide an improved ball and an improved method of making the same wherein a very high internal gas pressure may be obtained after the ball,

for convenience of manufacture, has been constructed by applying a strain-resisting struc- 1o ture, under comparatively low tension, to a solid core structure.

Another object is to provide conveniently for equalizing the tension of the inner and the outer layers of the rubber winding of a golf ball or the like, wherein the constricting force of the last applied turns of the winding compress and lessen the tension of theunderlying turns of the winding, and wherein subsequent expansion of thestructure by internal gas pressure, as a matter of geometry, effects a greater percentage of stretch of the inner than of the outer plies and thus equalizes, to an appreciable extent, the tension of the winding.

Another object is conveniently to provide a ball comprising a wound tension element held under high tension by the pressure of a gas enclosed therein, withoutmutilation of the tension element, after the winding thereof. for the insertion of pressure fluid.

In attaining these objects in the manufacture of a rubber-wound golf ball, for example, I employ a core consisting of an envelope enclosing a mixture of substancesin solid form adapted, upon being heated only to a temperature such as not to destroy the. tension of the rubber winding, to produce a gas of such quantity as to give the desired'high pressure, and preferably an inert gas adapted to be effectively retained by a rubber envelope.

I find that a mixture of ammonium. chloride and sodium nitrite, in the ratio of fifty per cent of each by weight, giving a chemical excess of the nitrite to avoid harmful effects of residual ammonium chloride, serves adinirably for the purpose stated, one gram of the ammonium chloride and sodium nitrite providing one hundred cubic centimeters of free nitrogen, which has the advantages of being highly inert and of being effectively re- I tamed by a rubber envelope.

In order to obtain a determinate pressure within the ball and at the same time provide a spherical pellet of the proper size for the winding of the rubber or other thread thereon I mix the ammonium chloride and sodium nitrite with a diluent of solid form, such as magnesium sulphate (Epsom salts), which not only acts as a diluent but also provides,

. when moderately heated, a moist condition be varied so as to provide a pellet of the right."

size and at the same time provide the desired gas ressure. 1

O the accompanying drawings: Fig. 1 1s an elevation, with a part sectioned and made in accordance with my invention in its preferred form as applied to golf balls.

and broken away, of a golf ball embodying" Fig. 2 is a similar view of a baseball illustrating a modification.

The spherical pellet of ammonium chloride, sodium nitrite and magnesium sulphate mixed in suitable proportions and pressed to shape, is shown at 10, in Fig. 1, the pellet being enclosed in a rubber envelope 11-, which may be applied to the pellet in the form of hemispherical shells, the shells then being joined in a circumferential seam by low temperature vulcanization or otherwise, or the pellet may be simply enclosed in a vulcanized rubber bag and the bag held closed by a string tied about the neck thereof.

' The rubber envelope may be provided with a gelatine lining 12 if desired, to lnsure against leakage of gas, but such lining may be. dispensed with without much leakage of gas through the rubber when nitrogen-producing materials are used for providing the gaseous core.

pansive force of the gas upon the stretching of the rubber winding and thus to prevent excessive expansion of the structure. When the winding is completed the last applied end thereof is anchored by tucking it under one or more turns of the winding and'th-e wound structure with the rubber-enclosed pellet therein is heated to such moderate temperature, which preferably is between 90 and 150 F., as to cause the ingredients of the pellet to react, which produces a quantity of nitro en depending upon the proportions an quantities of the materials used and which, by careful weighing of the materials, may be so accurately predetermined as to give the desired size in the wound structure after the reaction, notwithstanding the elastic character of the winding.

Preferably the pellet is so prepared as to cause the rubber winding to expand appreciably and thus to increase the tension of the inner plies of the winding by a greater percentage than that of the outer plies, and to give the Winding as a whole a very high tension even though it is initially wound under only moderate tension, for ease of winding and avoidance of breakage in the thread during the winding.

After the reaction is completed the usual gutta percha cover 14, or any other suitable covering, is applied-to the wound structure, and the ball is thus completed.

Alternatively the gutta percha or a similar 'moldable covering material may be applied to the wound structure and the covered structure enclosed in a mold before the chemical reaction is effected. The mold is then heated to soften and plasticise the covering material and to produce the chemical reaction, which expands the ball in the mold and thus shapes the cover. The mold preferably is then cooled before the removal of the finished ball therefrom. In this procedure the pellet preferably is so prepared that nearly all of the force of the gas in the finished ball will be sustained by the winding and only'a small part of it by the molded cover, and the gas pressure also may be so predetermined that upon. cooling of the mold the cooled cover, interlocked with the winding in the molding operation, will not be required to sustain any of the gas pressure.

In the baseball shown in Fig. 2 a winding 15 of fibrous thread is substituted for the rubber winding 13 of Fig. 1, a leather baseball cover 16 is shown, and the core is shown as being filled with gas and a small quantity of ash 17 resulting from the chemical reac-- tion.

I claim:

'1. The method of making a ball which comprises winding a covering layer of strip material upon a core comprising a mixture of materials in solid form adapted to react to produce a gas and causing the said materials so to react.

2. The method of making a ball which comprises winding a covering'layer of strip rubber under tension upon a core comprising a mixture of materials in solid form adapted to react to produce a gas at a temperature so low as not to destroy the tension of the winding and causing the said materials so to react.

3. The method of makin a ball which comprises winding a covering layer of strip material upon a core comprising a materlal in solid form adapted to produce a gas, enclosing the wound structure with a layer of moldable covering material in a mold, and effecting the production ofthe gas to expand the ball structure in the mold. 1

4. The method of making a ball which comprises winding a layer of strip rubber under tension upon a core comprisin a gas forming material, enclosing the woun structure with a layer of moldable covering material in a mold, causing the first said mate-' rial to form a gas and thus to expand 'the ball structure in the mold, the quantity of gas produced being so controlled as to cause substantially all of the force thereof to be sustained by the rubber winding in the finished ball at ordinary temperatures.

5. The method of making a ball which comprises winding a covering layer of strip material upon a core comprlsing a mixture of ammonium chloride and sodium nitrite and effecting chemical reaction of the mixed materials by heating the wound structure.

In witness whereof I have hereunto set my hand this 24th day of October, 1927 JOHN R. GAMMETER.

The several objects above set out are thus attained, and as my invention is susceptible of modification without sacrifice of all of the advantages inherent in the specific procedure a and structure herein described I do not whol 1y limit my invention thereto. 

